File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt
new file mode 100644
index 0000000..fe8150b
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/syscon.txt
@@ -0,0 +1,20 @@
+* System Controller Registers R/W driver
+
+System controller node represents a register region containing a set
+of miscellaneous registers. The registers are not cohesive enough to
+represent as any specific type of device. The typical use-case is for
+some other node's driver, or platform-specific code, to acquire a
+reference to the syscon node (e.g. by phandle, node path, or search
+using a specific compatible value), interrogate the node (or associated
+OS driver) to determine the location of the registers, and access the
+registers directly.
+
+Required properties:
+- compatible: Should contain "syscon".
+- reg: the register region can be accessed from syscon
+
+Examples:
+gpr: iomuxc-gpr@020e0000 {
+	compatible = "fsl,imx6q-iomuxc-gpr", "syscon";
+	reg = <0x020e0000 0x38>;
+};